Equipment having an actuator, such as a hydraulic cylinder, is equipped with a filter device for filtering fluid such as operating oil that circulates in a hydraulic circuit. The filter device is provided with a filter element that filters fluid that is to be filtered within the system.
When a filter device is used beyond a certain period of time, the performance of the filter element degrades due to clogging and the like, and is therefore replaced.
This type of filter device is provided with a head that is coupled to a hydraulic circuit and that has an inlet for the inflow of fluid that is to be filtered and an outlet for returning the filtered fluid to the hydraulic circuit, a filter element, and a housing that contains the filter element, the housing also being coupled to the head. The filter element can be replaced by removing the housing.
However, the place where the filter device is coupled to the equipment is not necessarily in a location that is suited for the operation of coupling the filter device.
In other words, depending on the place where the filter device is coupled, if one tries to couple these units to the head after placing the filter element into the housing, it is conceivable that this unit may have to be tilted. In such a case, it is conceivable that the filter element could come out of the housing.
For this reason, when coupling the filter device to the hydraulic circuit, the filter element is coupled and immobilized on the head in advance, after which the housing is coupled to the head.
However, the housing is typically a cylinder that is closed at one end, with the other end having an opening through which the filter element is introduced to contain it, and said opening is covered by the head.
Accordingly, when the housing is coupled to the head after a filter element is coupled to the head, as described above, the housing becomes coupled to the head while containing the filter element.
In other words, the operating space for coupling the housing must be sufficient to accommodate the combined height of the filter element and the height of the housing. It is difficult to ensure such space.
For that reason, a filter device has been proposed with an element pressing member provided separately from the filter element, to prevent the filter element from coming out of the housing. In this type of filter device, the filter element is immobilized within the housing by installing an element pressing member after inserting the filter element into the housing. The filter element is thus prevented from coming out of the housing.
This type of filter device makes it possible to reduce the operating space required while coupling the housing to the head.